Question

The ratio of the two unequal sides of a rectangle is $1:2$. If its perimeter is $24cm$ then length of diagonal is

• A. $\frac{2}{\sqrt{5}}$ cm
• B. $\frac{4}{\sqrt{5}}$ cm
• C. $4\sqrt{5}$ cm
• D. $2\sqrt{5}$ cm

Answer 1

Answer: (C)

$4\sqrt{5}$ cm

$L:B=1:2;L=x,B=2x$
$2(L+B)=24$
$\Rightarrow 3x=12\Rightarrow x=4$
Thus, two sides are 4 cm & 8 cm.
$Diagonal=\sqrt{4^2+8^2}=\sqrt{80}=4\sqrt{5}cm.$